A basic question that arises in cultural evolution is: is there cultural common descent. Are all the memes in the world related?
Cultural common descent is a problematical idea. For one thing, different creatures may well have came up with cultural transmission independently - e.g. humans and songbirds.
Even if we confine the discussion to humans - there are creole languages out there and other kinds of de novo culture.
Interestingly, lack of common descent in cultural evolution would pretty-much destroy the concept of common descent - when applied to the evolutionary process as a whole. Perhaps think about that for a moment.
However, novel memes which have no cultural parents - in a sense - could be considered to be the "descendants" of the creatures that created them - their "mind children" - so to speak. In that case, the common ancestor of all memes would be a primitive organic creature somewhere.
I think it is better to adopt this interpretation than to sacrifice common descent. Memes are another case of life coming from life - and do not represent a form of de novo creation.
Others may find the idea of organic creatures being the ancestors of memes impossible to swallow - and prefer to embrace the idea of de novo creation of memes. Those people would have to reject the doctrine of common descent, and embrace a view of the history of life that permits multiple origins.